The Evaluation of Front Shapes of Through-the-Thickness Fatigue Cracks

Fatigue failure of structural components due to cyclic loading is a major concern for engineers. Although metal fatigue is a relatively old subject, current methods for the evaluation of fatigue crack growth and fatigue lifetime have several limitations. In general, these methods largely disregard the actual shape of the crack front by introducing various simplifications, namely shape constraints. Therefore, more research is required to develop new approaches to correctly understand the underlying mechanisms associated with the fatigue crack growth. This paper presents new tools to evaluate the crack front shape of through-the-thickness cracks propagating in plates under quasi-steady-state conditions. A numerical approach incorporating simplified phenomenological models of plasticity-induced crack closure was developed and validated against experimental results. The predicted crack front shapes and crack closure values were, in general, in agreement with those found in the experimental observations.

Automated summary

This paper addresses the issue of fatigue failure of structural components under cyclic loading, proposing new tools to evaluate crack front shape and developing a numerical approach to model plasticity-induced crack closure. The predicted crack front shapes and closure values were validated against experimental observations, showing good agreement.